Being crowned the 'Best Beer in Britain' will more than double sales of Castle Rock's Harvest Pale ale over the next year, the brewer's chairman has predicted.

The 3.8% abv pale ale was awarded the Great British Beer Festival's highest accolade this week, prompting Nottingham-based Castle Rock to tip the drink to double its £800,000 off-trade sales over the coming 12 months. "A big area of growth for us now is bottled beer into the off-trade," said Chris Holmes, chairman of Castle Rock.

The brewer said it would meet the increased sales demand resulting from the win and ensuing publicity through a new brew house that is set to open in two weeks' time, enabling it to treble capacity.

Former winners of the award have typically seen sales increase by at least 40% year on year, according to Roger Protz, a member of the judging panel and author of the Good Beer Guide.

"In the past, one or two other winners were inundated and had to get other breweries to produce the beer in sufficient quantities to meet demand," he said.

The bottled version of Harvest Pale has regional distribution at Tesco and is available nationwide at Morrisons.

Any regional beers that perform and "stick their heads above the parapet" were considered for a national listing, according to Tesco beer buyer Ian Targett. The retailer had extended its local ale offering from 30 to 250 brands over the past five years, he said. Local beers make up 17% of its bottled ale sales.

"There were fewer large brewers and more smaller brewers at the festival this year, which is great for the category and points to increasing interest and passion for different, regional and local beers," said Targett.

Supermarkets were already doing a "wonderful job" with premium bottled ales, added Holmes, whose beers are distributed to the off-trade via PLB.

"For breweries like ourselves, the premium bottled ale category is fantastic," he said. "It's a completely different sector from 'pile it high and sell it cheap'. A lot of micros and smaller breweries are looking at it."